Asphalt cutter



J. SIRACUSA ASPHALT CUTTER July 14, 1925.

2 Sheets-Sheet 2 Filed March 11, 1924 Patented July 14, 1925. p

" UNITED STATES" PATENT ounce.

JAMES SIR-ACUSA, orB rFALo, NE YORK, AssIeuo To ROCK ASPHALT & cou- STRUCTION oo ino, or BUFFALO, NEW YORK, A CORPORATION OF NEW YoRK,

v ASPHALT oUT R.

Application filed March 11, 1524. Serial N'o. 6983394.

To all whom it may concern:

Be it known that 1, JAMES. SIRACUSA, a citizen of the United States, residing at Buffalo, in thecounty of'Erie and State of New York, have inventeda new and useful Improvement in Asphalt Cutters, of which the following is a specification.

.This invention relates to a hammer operating mechanism such as now commonly employed in asphalt cutters of that type in which the cutting is effected by means of a hammer adapted to be lifted by power and todrop by gravity for driving the knife orblade thereon into the asphalt, although the same may also be used for other purposes.

The objects of this invention are toprovide means for controlling the operation of lifting and releasing the hammer so that thelat-terv when free will be practically unrestrained by gearing and thus permit the weight of the hammer to operate more'effec tively in driving'the knife into the asphalt;

also to quickly release the hammerfrom the lifting mechanism so that the hammer can begin its descent instantly after such release and permit it to accelerate its downward movement rapidly and thus improve its driving blow on the knife; to so construct the means for coupling and uncoupling the hammer lifting means with the power mech anism that this operation is effected quickly and with a minimum of friction and wear on the parts; and to provide means for accomplishing this purpose which'are simple and durable in construction, eflicient and. re-

liable in operation, and not liable toget out of. order due to vibration and hard; usage to which they are subjected. I

In the accompanying drawings:

Figure 1 is a vertical transverse section of', an asphalt cutter illustrating diagrammatically one machine in which my invenline 9-9, Fig. 5. Figures 1.0 and 11 are vertical longitudinal sections taken on line 10-11, Fig. 5 and showing the parts in different positions. V Similar characters of reference indicate like parts throughout the several views.

The numeral 20 represents the frame or body of the car or vehicle upon which theasphalt cutting mechanism. is mounted and transported while in use or from one piece of work .to another for which purposethis frame is mounted on wheels '21 (and may b propelled in any suitable manner.

Movable vertically in suitable upright ways 22 on the main frame is a hammer or sliding weight 23 which is provided on its underside with a knife or blade 24 adapted to strike. the asphalt underthe weight of a blow of the hammer and cut a slit or groove into the same so as to permit the same. to be subsequently easily removed from the street in case of repairs or when preparing the same for digging a trenchto-receive sewer gas, water pipes or electric conduits.

This lifting of the hammer is preferably effected bya chain belt 25 passing with its upper turn over a guide pulley 26 on top of the main frame and having the lower end of its outer stretch connected with the hammer and the lower end of its inner stretch connected with the periphery of a hoisting. drum 19. The latter is mounted loosely on a horizontal hoisting shaft 27 journaled in suitable bearings 28, 29 on the main frame and is adapted alternately tobe connected with a power mechanism whereby the same is turned forwardly for causing the lifting chain to wind thereon and lift the hammer and to be disconnected therefrom to permit the drum to turn backwardly and the hammer to descend as the lifting chain I groove or jaw 31 which is of tapering formin cross section, and a driving'clutch wheel or disk 32 secured to the hoisting shaft and provlded on one side with an'annularclutch,

.rib or jaw 18 oftapering form in cross section and adapted to' engage the clutch groove in the driven clutch disk. The driving clutch disk turns continuously in the same direction when the machine is in operation by power derived from any suitable source. For instance, as shown in Figure 1, this may be accomplished by means of a gas "engine 33 mounted on the lower part of the main frame and having its shaft 34 provided with a gear wheel 35 from which motion is transmitted to a gear wheel or rim 36 on the driving clutch disk by means of an intermediate gearwheel 37 mounted on the main frame. Upon moving the driven clutclrdisk axially toward the driving clutch disk these two disks will be coupled and the hoisting drum will be turned forwardly so as to wind the hoisting chain thereon and lift the hammer. Upon moving the driven disk axially away from the driving disk these disks will be uncoupled and allow the hammer to fall during which time the lifting chain unwinds from the hoisting drum and the latter is turned backwardly. The clutch disks are yieldingly held apart by a spring 38 interposed between the same and the rotation of the .drum is either controlled or pre vented by a brake band 39 adapted to be moved into and out of gripping engagement with the peripheryof the driven clutch disk by means of a lever 40 mounted on the main frame.

V The movement of the driven clutch disk toward thedriving clutch disk is effected by the following means:

The numeral 41 represents an abutment collar secured to the hoisting shaft on that end thereof opposite the end which is connected with the driving clutch disk. Between the abutment collar and the hub of the hoisting drum and driven clutch disk isarranged a pair of cam disks 42, 43, the opposing sides of which are in engagement and have the form of cams or wedges so that upon turning these cam disks forwardly or in one direction these disks will be spread apart in a direction lengthwise of the axis ofthe hoisting shaft while upon turning these disks ba'ckwardly or in the opposite direction "the same will be permitted to approach each other. The thrust thus exerted hythecam disks upon turning the same forward-1y is caused to move the driven clutch disk into engagement with the driving disk, this being preferably effected by interposing a ball thrust bearing 44 between the rear side-of the cam disk '42 and the hub of the hoisting drum and driven clutch disk and a similar thrust ball bearing 45 between the thrust and collar 41 and the rear side of the cam disk 43. In order to. permit of adjusting'the-vrelation of the cam disks relatively to-eacli other and to'take up wear on the parts between the thrust collar 41 and the driving clutch disk, means are provided which preferably consist in providing the outer side of themcam. disk '43 with. an ad justing sleeve 46 having a screw connection with the cam disk 43 and engaging the outer ball bearing 45, as shown in Figures 2 and 4. Turning of the cam disks forwardly and backwardly relatively toward each other is effected by means which comprise a vertically swinging shifting lever 47 pivoted at one end on the main frame, .two links 48, 49 having their upper ends pivotally connectedwith the shifting lever while their lower ends are respectively pivotally connected with the cam disks 42, 43, on diametrically opposite sides of the axis about which'they turn, as shown in Figures 7 and 8. The cam faces of the cam disks are-so constructed that upon raising the shifting lever 47 as shown in Figure 7 ,the cam disks are permitted to approach each otherand uncouple the clutch so as to release the drum and permit the hammer to drop, while upon lowering the shifting lever, as-shown in Figure 8, the cam disks will be spreadto cause the driving and driven clutch disks to be coupled or closed and the. drum to lift the hammer.

- The raising and lowering of the shifting lever is effected automatically and periodically so that the clutch will be opened the instant the hammer reaches the desired height and the clutch is again closed during the last part of the downward stroke of the hammer preparatory to again elevating the same. This operation is effected by an automatic controlling mechanism which is constructed as follows:

The numeral .17 represents abhorizontal controlling shaft journaled transversely in suitable bearings 15, 16 on the main frameso that the same is parallel with the clutch and drum shaft, as shown in Figures 2 and 3. The shaft is yieldingly held. against turning by a frictional resisting device which in its preferred form, as shown in Figures 2 and 3, comprises a. fixed friction disk 51 arranged on the bearing 15, a movable friction disk 52 engaging the fixed friction disk and connected by aspline 53 with the controlling shaft so as to be free to move lengthwise on this shaft but compelled to turn therewith, and a spring 54 interposed between the rear side of the movable fric-- tio-n disk and an abutment collar 55 secured to the controlling shaft. V i

The free end of the cam disk shifting lever is preferably constructed in the form of a fork and its upper and lower tines or branches 56, 57 engage withop-posite sides of a rotary 'controllingor lifting cam 58 which is secured tofthe controlling shaft.

A ball thrust bearing 59 is interposed be tween the hub of the liftingcam 58- and the adjacent bearing 1 6 on the main frame for the shaft 17 o The numeral 60 represents a driven controller sprocket wheel mounted loosely on Inn the controlling shaftv and 61 represents a chain belt passing around. this driven sprocket wheel and a driving controller.

sprocket wheel 62 on the hoisting drum. On one side of the driven-controller wheel the same is provided with a tappet 63 which preferably has the formof an eccentric which is adjustably mounted on the controller wheel 60' by means of a pivot and clamping screw 6 This tappet is adapted to engage alternately with opposite sides of a tappet arm 65 secured to the controller shaft 17. I

The operation of this; mechanism is as follows r I In Figures 3, 4t, 6, 7 and 9 .the parts are shown; in the position which they occupyv when the clutch is released, and the'hammer has been permitted to .drop by gravity and produce an incision of the knife in the asphalt, At this time the lifting cam 58 has its salient part in its highest position,

the tappet engages with the underside of the tappet arm on one side of the axis of the controller shaft, and links are raised by the controlling lever and turn the cam disks so that'the low part of the cam face on each of these disks is opposite the high part of the cam face of the other cam disk. The parts have been brought to this position by the forward rotation of the hoisting drum while the same was coupled with themotive power and the hammer was being lifted, the direction of movement of the drum at this time being indicated by the arrow in Fi 118 2. The instant the hammer has reached the highest position which has been predetermined and the drum has been disdrum. Asthe driven sprocket wheel 60 turns backwardlythe tappetcarried by the same firstinoves idly out of engagement from the underside of the tappet arm and'independently therefrom until the tappet has made nearly a complete turn about the axis of the controller shaft and thus engages with the upper side of the tappet arm. Thereafter the tappet during its continued backward rotation carries backwardly with it the tappet arm until the latter has made one half a rotation about the axis of the controller shaft, and has carried the same from .the position shown by. full lines in Figure .9 to the position shown bydottedlines in the same figure. :-As a result of the action the lifting cam is reversed so that its salient part is carried from a position in timed that this uncoupling occurs during the last part of the downward movement of so. I

the hammer, so that the clutch is coupled and lifting of the hammer commences immediately after the knife strikes the. asphalt. This upward movement of the hammer continues until the drum during its forward or. winding movement has first moved the tappet idly' from the underside of the tappet arm, as shown by dotted lines in Figure 9, nearly a full turn about the axis of the controller shaft until it engages with the upper side of the arm after which the tappet and tappet arm move forwardly together until the latter has turned 180 degrees and the'lifting cam 58 has been moved from the pendent position shown by dotted lines in Figure 9, to the upstanding position shown by full. lines inthe same figure. When. the lifting cam 58 reaches this position the lifting lever turnsthe cam disks in a direction for removing the thrust against .thedriven clutch disk and permitting the spring 38 to open the clutchand thus release the hoisting drum so that it can turn backwardly and permit the hoisting chain to unwind therefrom under the pull of the hammer which at this time is free to descend and deliver a blow of its blade into the asphalt surface of the pavement. During the continued use of the machinethis cycle of operation is repeated continuously in the manner described.

In the drawings the driving controller sprocket wheel 62 is represented as being somewhat larger than the driven controller sprocket wheel 60 but the relative size. of these 'wheels may be altered as required de-. pending on the size of the hoisting drum and the rate of speed. at which the hoisting is to be effected.

By adjusting the eccentrically shaped taps pet about its pivot and clamping screw on the driven controller sprocket wheel the height to which the hammer is lifted at each stroke before it is released may be varied and thus permit of adjusting the blow of the hammer according to the hardness of the asphalt, the same being comparatively hard and requiring a heavier blow of thehammer in. cold weather, while in warmweatherv the same is comparatively soft, and therefore a lighter blow of the hammer will suffice to drive the knife the requisitedepth into the asphalt.

-Owing to the quick release of the drum from the power mechanism when the hammer reaches the top of its stroke it is possible for the hammer to begin its descent instantly and owing to the complete disconnection thus effected between these parts it is possible'for the hammer to drop without undue restraint and thus rapidly accelerate its speed and deliver the most effective blow, thereby enabling the machine to work with greater efficiency and increase the amount of work done within a given time, whereby a corresponding. saving in cost is effected. Furthermore the several parts of this ma chine are of simpleconstruction, they are not liable to get out of order and can readily be replaced when worn.

. Obviously this hammer operating mecha nism can be used in analogous machines, such as pile drivers, and forging machines.

I claim as my invention r '1. A hammer operatingmechanism of the character described comprising adriving clutch member, a driven clutch member adapted to engage said driving clutch memher, a controlling shaft which is rotated by motion derived from said driven clutch member, and meansactuated by said controlling shaft and operating :to engage said clutch members, comprising a cam mechanism operating on said driven clutch member, a rock lever connected with said cam mechanism, and a controlling cam mounted on said controlling shaft and engaging with said rock lever.

2. A hammer operating mechanism of the character described comprising a driving clutch; memlber, a driven ,clutch member adapted to engage saiddrivingclutch meniher, a controlling shaft which is rotated by motion derived from said driven clutch member, and means actuated by'said controlling shaft and operating to engage said clutch members comprising tWo rotary cams having opposing cam faces which engage with each otherand one of said'cam disks exerting a thrust against said driven clutch disk, an abutment which receives the thrust of the other cam disk, a rock lever connected with said cam disks onopposite sides of the axis of said disks, and a controlling cam arranged on said controlling shaft and engaging with said lever.

3. A hammer operating mechanism of the character described comprising a driving clutch member, a driven clutch member and means for pressing said driven member toward-said driving member and releasing the same including a controlling shaft, a cam mechanism adapted to press saiddriven clutchmember toward said driving member, a rocklever connected with said cam mechanism, a controlling cam secured to said shaft and engaging with said rock lever, a tappet rotatably mounted on said shaft, means for rotating said tappet, and a tappet arm secured to said shaft and adapted to be engaged by said tappet.

4. A hammer operating mechanism of the character described comprising a drivingclutch member, a driven clutch member and means for pressing said driven member toward said driving member and releasing the same including a controlling shaft, a cam mechanism adapted to press said driven clutch member toward said driving member, a rock lever connected with said cam mechanism, a controlling cam secured to said shaft and engaging with said rock lever, a driving wheel connected with said driven clutch member, a driven wheel mounted on said shaft, a belt passing around said drivy ing and driven wheels, a tappet arranged on said driven wheel and a tappet arm secured to said shaft and adapted toiengage with said tappet. I

5. A hammer operating mechanism of the character described comprising a driving clutch member, a driven clutch member and means for pressing said driven member toward said driving member and releasing the same including a controlling shaft, a cam mechanism adapted to press said driven clutch member toward said driving memher, a rock lever connected with said cam mechanism, a controlllng cam secured to said shaft and engaging with said rock lever, V

the same including a controlling shaft, a

cam mechanism adapted to press said driven clutch member toward said driving member, a rock lever connected with said cam mecha nism, a controlling cam secured to said shaft and engaging with said rock lever, a tappet rotatably mounted on said shaft, means for rotating said tappet, a tappet arm secured to said shaft and adapted to be engaged by said tappet, and means for retarding the rotation of said shaft.

i 7 A hammer operating mechanism of the character described comprising a drivin clutch member, a driven clutch member an means for pressing said driven member toward said driving member and releasing the same including a controlling shaft, a cam mechanism adapted to press said driven.

clutch member toward said driving member, a rock lever connected with said cam mechanism, a controlling cam secured to said shaft and engaging with said rock lever, a tappet rotatably mounted on said shaft, means for rotating said tappet, a tappet arm secured to said shaft and adapted to be en gaged by said tappet, and means for retarding the rotation of said shaft comprising a stationary friction disk surrounding said shaft, a movable friction disk slidable lengthwise on the shaft but compelled to turn therewith, and a spring for pressing slaii movable disk against said stationary 8. A hammer operating mechanism of the character described comprising a driving clutch member, a driven clutch member and means for pressing said driven member to ward said driving member and releasing the same including a controlling shaft, a cam mechanism adapted to press said driven clutch member toward said driving member, a rock lever connected with said cam mech anism, a controlling cam secured to said shaft and engaging with said rock lever, a tappet rotatably mounted on said shaft, means for rotating said tappet, a tappet arm secured to said shaft and adapted to be engaged by said tappet, and means for retarding the rotation of said shaft comprising a stationary friction disk surrounding said shaft, a movable friction disk slidable lengthwise on the shaft but compelled to turn therewith, a spring for pressing said movable disk against said stationary disk, and an abutment for said spring on said shaft.

9. A hammer operating mechanism of the character described comprising a driving clutch member, a driven clutch member and means for pressing said driven member toward said driving member and releasing the same including a controlling shaft, a cam mechanism adapted to press said driven clutch member toward said driving member, a rock lever connected with said cam mechanism, a controlling cam secured to said shaft and engaging with said rock lever, a tappet rotatably mounted on said shaft, means for rotating said tappet, a tappet arm secured to said shaft and adapted to be engaged by said tappet, and means for retarding the rotation of said shaft comprising a stationary friction disk surrounding said shaft, a movable friction disk slidable lengthwise on the shaft but compelled to turn therewith, a spring for pressing said movable disk against said stationary disk, and a thrust bearing which resists lengthwise movement of said shaft in a direction opposite to the longitudinal movement of said movable friction disk.

In testimony whereof I affix my signature.

JAMES sIRAcUsA; 

